Orthodontics is a specialty in dentistry that moves teeth within the jaw bone and straightens the teeth by moving them to the proper three-dimensional location. In orthodontics, brackets are pieces of metal with a slot that accepts a flexible or rigid metallic wire. Such brackets are conventionally bonded to the teeth on a base (via a frame) and serve as vehicles allowing the orthodontist to apply force to the tooth to move it across the wire to its proper location with the proper angulation.
The interaction of force, wires and brackets guides the three dimensional movement of the tooth. The force applied to the teeth, by the wire, forces the teeth to slowly alter their positions to align with the wire and therefore position them correctly in three dimensions.
Conventional brackets generally have a fixed slot wherein the position of the slot relative to the tooth is fixed. Historically, brackets were the same for all teeth, regardless of patient individuality. Since every tooth has a unique three dimensional relationship with the rest of the teeth, the orthodontist was required to bend the wire that passed across the bracket slot in order to correct tooth angulation for each individual tooth.
In orthodontics, the angulation of the bracket slot in each dimension is described differently. The angulation of the bracket slot in the left-right direction is called ‘tip’ and the angulation of slot in the back-forward direction is called ‘torque’. An average tip and torque has been calculated for every tooth, based on studies of normal dentitions. A modification was presented a few decades ago by which specific brackets were created for every tooth according to their average angulations so that when a straight wire was passed through the slot, the difference between the angle of the straight wire and the angle of the slot would force the tooth to track the wire and achieve the proper angulation. However, the inaccuracies occurred when a bracket was not bonded to the proper location on the tooth, which led to an improper angulation of the tooth and ultimately to a misaligned tooth.
Also, the presumed angulations are merely averages, based on estimates of average sizes and shapes of teeth. Each individual is different with varying morphology for their teeth. Whenever a patient's teeth do not fall within the normal range, the straight wire technique does not produce optimum tooth angulation and location. Commonly, brackets are not always placed in the proper location on the tooth resulting in erroneous bracket positioning. In order to correct for such problems, a certain number of brackets are repositioned during the course of the treatment to address these inaccuracies and improper bracket placements. Repositioning is both time-consuming and expensive and oftentimes does not cure the improperly positioned bracket. The process of bracket repositioning involves a patient's office visit, removal of the old bracket, polishing of the tooth surface, priming of the surface and application of the new bracket to the surface. This process can take anything from 5 to 15 minutes per tooth, depending on the location of the bracket and the experience of the clinician.
A need exists for a dynamic bracket system that allows the clinician to change the angulation of the bracket to achieve proper tooth alignment. A further need exists for a dynamic bracket system that allows a change in angulation in a number of different directions. Yet a further need exist to do so using a system that is efficient, easy to adjust and cost effective.